Printed inverted L antenna on dielectric substrate excited by microstrip line

A printed inverted L antenna on a dielectric substrate excited by a microstrip line is proposed and numerically analyzed. The inverted L antenna is printed on the surface of the upper dielectric substrate and the microstrip line is printed on the back surface of the lower dielectric substrate. On the conducting plane between two dielectric layers, a slot is located near the base of vertical element of inverted L antenna. The design frequency is 24 GHz. The antenna size is 3 mm (0.24 ?) by 6 mm (0.48 λ) by 0.436 mm (0.035 λ). λ is the wavelength at 24 GHz. The length and width of horizontal element of inverted L antenna are 1.8 mm (0.144 λ) and 0.6 mm (0.128 λ), respectively. The S11 less than -10 dB is satisfied from 23.9 GHz to 24.06 GHz. The directivity of 4.75 dBi is obtained at the design frequency of 24 GHz.